1. Field of the Invention
The invention is directed to blends of olefinic thermoplastic vulcanizates with high impact polystyrene utilizing a flexible block copolymer as compatabilizer.
2. Description of the Prior Art
Blends which have combination of both thermoplastic and elastic properties are generally obtained by combining a thermoplastic resin with an elastomeric material in a way such that the elastomer is intimately and uniformly dispersed as a discrete particulate phase within a continuous phase of the thermoplastic. Early work with the vulcanization of the elastomer phase is found in U.S. Pat. No. 3,037,954 which discloses static vulcanization, as well as dynamic vulcanization wherein a vulcanizable elastomer is dispersed into a resinous thermoplastic polymer and the elastomer is cured (crosslinked) while continuously mixing and shearing the blend.
In International Patent App. No. PCT/US01/02482, there is described a thermoplastic elastomer which has been modified by the addition of a vinyl aromatic block copolymer. The compositions of the invention have improved adhesive properties with respect to polymeric substrates, particularly with respect to engineering thermoplastics.
However, previous attempts at blending of thermoplastic vulcanizates with a rubber-modified monovinylidene aromatic polymeric component, specifically high impact polystyrene, have been unsuccessful.